South Dakota voters made history last November by simultaneously approving ballot initiatives aimed at legalizing recreational and medical use of marijuana. The success of the broader initiative, Amendment A, was especially striking because it prevailed by an eight-point margin in a state that is mostly Republican and largely conservative. But thanks to a legal challenge backed by Republican Gov. Kristi Noem, Amendment A was almost immediately tied up in litigation, and last Wednesday the South Dakota Supreme Court definitively overturned it, ruling that the measure violated the “single subject” rule for constitutional amendments.

The court’s 4–1 decision does not affect Measure 26, which authorizes medical use of marijuana and passed with support from 70 percent of voters last November. But unless the state legislature independently implements the policy embodied in Amendment A, the ruling means supporters of broader legalization will have to try again next year with an initiative that addresses the court’s legal objections.

Article XXIII, Section 1 of the South Dakota Constitution says “a proposed amendment may amend one or more articles and related subject matter in other articles as necessary to accomplish the objectives of the amendment,” but “no proposed amendment may embrace more than one subject.” According to the South Dakota Supreme Court, that rule aims to “prevent the ‘pernicious practice’ of combining unrelated provisions in one amendment to ensure passage of a provision that might otherwise fail had the provisions been submitted separately.” [Read more at Reason Magazine]